Which of the following is NOT an application of biotechnology?

Conventional hybridisation

The answer is (d). Conventional hybridization is not an application of biotechnology. 

Conventional hybridization is a traditional breeding technique that involves crossing two different plants or animals to create offspring with desirable traits. It is not considered a part of biotechnology, as it does not involve genetic modification or manipulation at the molecular level. Biotechnology, on the other hand, includes various applications like waste treatment, energy production, and the use of genetically modified crops for agriculture, among others, which involve advanced genetic engineering and molecular techniques.

The other options are all applications of biotechnology. Waste treatment uses biotechnology to break down organic waste into harmless substances. Energy production uses biotechnology to produce fuels and other energy sources. Genetically modified crops are crops that have had their DNA altered to improve their traits.

So the correct answer is (d). Conventional hybridization is not an application of biotechnology.